1. Field of the Invention
The invention relates first to a radial piston pump for producing high fuel pressure in fuel systems of internal combustion engines, in particular in a common rail injection system, with a housing that has at least one cylinder, with a drive shaft that is supported in the housing and has at least one cam section, with a stroke ring that is disposed encompassing the cam section, and with at least one piston that is contained in the cylinder and is supported against the stroke ring.
2. Description of the Prior Art
A radial piston pump of the type with which this invention is concerned is known from DE 198 58 862 A1. In it, three cylinders are arranged in the form of a star around a cam section of a central drive shaft. A stroke ring is placed onto the cam section and is connected to the radially inner ends of the pistons contained in the cylinders. The stroke ring itself does not rotate, but moves along a circular path in its plane. This sets the pistons contained in the cylinders into a reciprocating motion.
A radial piston pump of this kind is used as a high-pressure fuel pump in a fuel system. It is supplied with fuel by a presupply pump and it sends the fuel on into a fuel accumulation line, also commonly referred to as a “rail”. From there, the fuel travels through injectors into combustion chambers of the engine.
In certain operating situations, it can be necessary to vary the quantity of fuel delivered by the high-pressure fuel pump to the fuel accumulation line. Usually, pressure control valves and/or quantity control valves are provided for this. Their operation causes pressure surges in the low-pressure region, which makes it necessary to install pressure dampers. Furthermore, the fuel accumulation line is provided with a pressure relief valve via which excess fuel delivered by the high-pressure fuel pump can be discharged from the fuel accumulation line.